tools/testing/selftests/bpf/progs/iters_css_task.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2023 Chuyi Zhou <[email protected]> */
   3
   4 #include "vmlinux.h"
   5 #include <errno.h>
   6 #include <bpf/bpf_helpers.h>
   7 #include <bpf/bpf_tracing.h>
   8 #include "bpf_misc.h"
   9 #include "bpf_experimental.h"
  10
  11 char _license[] SEC("license") = "GPL";
  12
  13 struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym;
  14 struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
  15 void bpf_cgroup_release(struct cgroup *p) __ksym;
  16
  17 pid_t target_pid;
  18 int css_task_cnt;
  19 u64 cg_id;
  20
  21 SEC("lsm/file_mprotect")
  22 int BPF_PROG(iter_css_task_for_each, struct vm_area_struct *vma,
  23             unsigned long reqprot, unsigned long prot, int ret)
  24 {
  25         struct task_struct *cur_task = bpf_get_current_task_btf();
  26         struct cgroup_subsys_state *css;
  27         struct task_struct *task;
  28         struct cgroup *cgrp;
  29
  30         if (cur_task->pid != target_pid)
  31                 return ret;
  32
  33         cgrp = bpf_cgroup_from_id(cg_id);
  34
  35         if (!cgrp)
  36                 return -EPERM;
  37
  38         css = &cgrp->self;
  39         css_task_cnt = 0;
  40
  41         bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS)
  42                 if (task->pid == target_pid)
  43                         css_task_cnt++;
  44
  45         bpf_cgroup_release(cgrp);
  46
  47         return -EPERM;
  48 }
  49
  50 static inline u64 cgroup_id(struct cgroup *cgrp)
  51 {
  52         return cgrp->kn->id;
  53 }
  54
  55 SEC("?iter/cgroup")
  56 int cgroup_id_printer(struct bpf_iter__cgroup *ctx)
  57 {
  58         struct seq_file *seq = ctx->meta->seq;
  59         struct cgroup *cgrp = ctx->cgroup;
  60         struct cgroup_subsys_state *css;
  61         struct task_struct *task;
  62
  63         /* epilogue */
  64         if (cgrp == NULL) {
  65                 BPF_SEQ_PRINTF(seq, "epilogue\n");
  66                 return 0;
  67         }
  68
  69         /* prologue */
  70         if (ctx->meta->seq_num == 0)
  71                 BPF_SEQ_PRINTF(seq, "prologue\n");
  72
  73         BPF_SEQ_PRINTF(seq, "%8llu\n", cgroup_id(cgrp));
  74
  75         css = &cgrp->self;
  76         css_task_cnt = 0;
  77         bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS) {
  78                 if (task->pid == target_pid)
  79                         css_task_cnt++;
  80         }
  81
  82         return 0;
  83 }
  84
  85 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
  86 int BPF_PROG(iter_css_task_for_each_sleep)
  87 {
  88         u64 cgrp_id = bpf_get_current_cgroup_id();
  89         struct cgroup *cgrp = bpf_cgroup_from_id(cgrp_id);
  90         struct cgroup_subsys_state *css;
  91         struct task_struct *task;
  92
  93         if (cgrp == NULL)
  94                 return 0;
  95         css = &cgrp->self;
  96
  97         bpf_for_each(css_task, task, css, CSS_TASK_ITER_PROCS) {
  98
  99         }
 100         bpf_cgroup_release(cgrp);
 101         return 0;
 102 }